public class MySqrt {
    public int code(int x) {
        if (x < 1){
            return 0;
        }
        long left = 0, right = x;
        while (left < right){
            long mid = left + (right - left + 1) / 2;
            long num = mid * mid;
            if (num <= x){
                left = mid;
            }else{
                right = mid - 1;
            }
        }

        return (int)left;
    }
}
